.child2-com {
  position: relative;
  width: 100%;
  height: 100%;
  .child2-tip {
    font-size: 30px;
    color: blue;
  }
  .child2-bg {
    position: relative;
    width: 400px;
    height: 300px;
    background: red;
    background-size: 100% 100%;
  }
}
